Passenger vehicles, such as automobiles and aircraft, often provide vehicle information systems, such as passenger entertainment systems, to satisfy passenger demand for entertainment and other information content during travel.
Conventional vehicle information systems include content presentation systems for presenting viewing content to the passengers. These vehicle information systems typically include one or more media servers for storing the viewing content as well as video presentation systems, such as overhead cabin display systems and/or seatback display systems, and audio presentation systems, such as overhead speaker systems and/or individual headphones, for presenting the viewing content. The viewing content can include audio and video content that are derived from a variety of sources. Prerecorded viewing content, such as motion pictures and music, can be provided by internal content sources, such as audio and video players, that are installed aboard the vehicle. The conventional vehicle information systems likewise can include an antenna system for receiving viewing content, such as live television programming, transmitted from one or more external content providers (or sources) remote from the vehicle.
The content providers often employ a variety of security techniques to protect the viewing content from unauthorized access. If the viewing content includes Moving Picture Experts Group (MPEG) Transport Stream video content, for example, the content providers typically use conventional file-based encryption techniques to protect the viewing content. Such encryption techniques, however, suffer from many disadvantages. For example, the content providers currently require that viewing content be stored in an encrypted format at all times, even by the media servers and/or portable media devices associated with the vehicle information systems. The vehicle information systems therefore must perform additional processing, such as decryption and/or decoding, on the encrypted viewing content to allow the viewing content to be presented. This additional processing typically imposes restrictions on the encryption block size of the viewing content.
The presentation of the viewing content thereby is adversely affected. During fast-forward, rewind and search operations, for example, a decryption/decoding system must advance to an unknown position within the encrypted viewing content file and then begin to decrypt/decode the encrypted viewing content starting at that position. The visual presentation of the viewing content thereby can appear jumpy and otherwise discontinuous. Further, by requiring that the encryption of the viewing content be maintained even during media loading and other preparatory processes, the content providers prevent the viewing content from being pre-scanned to create an index or associated file to help ensure smooth presentation of the viewing content during fast-forward and rewind operations.
In view of the foregoing, a need exists for an improved system for encrypting data, such as viewing content, that overcomes the aforementioned obstacles and deficiencies of conventional file-based encryption techniques.
It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the preferred embodiments of the present disclosure. The figures do not illustrate every aspect of the present disclosure and do not limit the scope of the disclosure.